Conventionally, in a magnetic recording medium such as a hard disc, various improvements such as miniaturization of magnetic particles forming a recording layer, material change for the magnetic particles, and increased precision in the head processing, have been made to largely improve areal density. A further improvement in the areal density is expected.
However, many problems including the limitation of the head processing, side fringes caused by broadening of a magnetic field, crosstalk, and the like are made apparent. Thus, the improvement in the areal density by the conventional improvement approach has reached the limit. Therefore, as a candidate of a magnetic recording medium that enables further improvement in the areal density, a discrete type magnetic recording medium in which a continuous recording layer is divided into a number of divided recording elements has been proposed, as described in Japanese Patent Laid-Open Publication No. Hei 9-97419, for example.
As a processing technique for achieving fine division of the continuous recording layer, dry etching processes as described in Japanese Patent Laid-Open Publication No. Hei 12-322710, for example, ion beam etching, and reactive ion etching using CO (carbon monoxide) gas with a nitrogen-containing gas such as NH3 (ammonia) gas added thereto as a reactive gas can be used.
As a technique for processing a mask layer for dry etching in a predetermined pattern, techniques used in the art of semiconductor manufacturing, such as lithography using a resist layer, can be used.